Hello. After upgrading from Hobernate 3.5 to 3.6 I have an error:

org.hibernate.event.def.AbstractFlushingEventListener - Could not synchronize database state with session
org.hibernate.HibernateException: Unknown unwrap conversion requested: java.sql.Blob to org.hibernate.type.descriptor.BinaryStream

My code:

@Lob
@Basic(fetch = FetchType.LAZY)
@Column(nullable = false, updatable = false)
public Blob getData() {
return data;
}

I use PostgreSQL and jdbc4 driver.

Can anybody help me with this error?

I had the same problem, finally fixed it by replacing Blob to byte[] and use the type "binary" rather than "blob"

hope this help